The present invention relates to processes for selectively comminuting impure psyllium seed husk. The present invention also relates to methods for purifying psyllium seed husk. Furthermore, the present invention relates to psyllium husk prepared by the processes of the present invention, and to psyllium-containing products (especially products to be mixed in liquids to form psyllium-containing drinks) comprising psyllium husk prepared by a process of the present invention.
The seed husk to be selectively comminuted by the process of the present invention is psyllium seed husk from psyllium seed, from plants of the Plantago genus. Various species such as Plantago lanceolate. P. rugelii, and P. major are known. Commercial psyllium seed husk includes the French (black; Plantago indica), Spanish (P. psyllium) and Indian (blonde; P. ovata). Indian (blonde) psyllium seed husk is preferred for use herein.
Products containing psyllium seed husk are used in high fiber food products and/or health care products for their benefit of normalizing bowel function and laxation. In addition, recent research has demonstrated the effectiveness of psyllium seed husk fiber in reducing human serum cholesterol levels, and in controlling blood glucose levels in diabetics. See, for example, J. W. Anderson, et al., Fed. Proc., 46. 877 (1987); J. W. Anderson, et al., Am. J. Gastroenterol., 81, 907-919 (1986); and S. Faberberg, Curr. Ther. Res., 31, 166 (1982); all incorporated herein by reference in their entirety.
Psyllium seed husk is typically manufactured by separating the seed husk from the remainder of the seed by slight mechanical pressure, for example by crushing the seeds between rotating plates or rollers. The husk is then typically purified by sieving the mixture to separate the husk from the remainder of the seed parts and/or by blowing (winnowing) the husk away from the impurities. Impurity present in the psyllium husk is predominantly dark particles which are readily visually apparent amongst the blond-colored psyllium husk; and are readily perceived as being particularly gritty during ingestion. Subsequent attempts at purifying the psyllium further, for example by sieving, are generally tedious processes which produce low yields of psyllium and/or only moderately improved purity.
While the selective comminution processes of the present invention are previously unknown and unexpected, mills suitable for these processes are known. Generally, they are characterized as being mills which produce fragmentation (i.e., the "milling") of materials through collision, including particle-particle collision (e.g., fluid energy mills) and/or particle-blunt surface collision (e.g., stud mills; ball mills), rather than having the fragmentation being caused solely by a crushing action or by scissoring, screening, abrading, shearing, or slicing actions.
Such mills have been used to mill a wide variety of materials. For example, materials such as silica gel, tungsten carbide, toner, wax, resin, fat, and mica have been milled in fluidized bed opposed jet mills; and materials such as acetyl salicylic acid, bran, sesame seeds, glucose, grains, and copper oxychloride have been milled in stud mills. Furthermore, selective grinding by fluidized bed opposed jet mills during the processing of foundry sand (to separate water glass bond or resin cement from the sand) and the cleaning of metal alloys (to separate mineral or ceramic contaminants from the main alloy) are known.
An object of the present invention is to provide processes for manufacturing high yields of higher purity psyllium seed husk. A further object is to provide processes for purifying impure psyllium seed husk. An additional object is to provide processes for making very fine particle size, high purity psyllium seed husk from impure psyllium seed husk (especially impure husk having about 95% or less purity). An additional object is to provide psyllium-containing products having better flavor, less grit, and/or lighter color comprising sized psyllium seed husk prepared by a process of the present invention.
These and other objects of the present invention will become readily apparent from the detailed description which follows.
All percentages and ratios used herein are by weight unless otherwise specified.